The present invention relates to a substrate cleaning apparatus used for cleaning a substrate to be cleaned, such as a semiconductor wafer, a LCD or the like.
In this type of conventional substrate cleaning apparatus mentioned above, for example, such a configuration has been provided, which comprises a scrub cleaning tool for cleaning a wafer by rubbing a surface to thereof with a brush or a sponge (cleaning tool), and a liquid jet spray nozzle for cleaning the wafer by jet-spraying high pressure water excited by ultrasonic vibration energy or cavitation onto the surface of the wafer, or the like. Each of these cleaning means are mounted on an individual arm, respectively, to be moved by a respective swinging arm between a center and a periphery of the wafer while rotating the wafer to clean the entire surface of the wafer.
A reason why a plurality of cleaning means are combined to clean the wafer is discussed below. That is, it is true that a cleaning method for cleaning the wafer by rubbing the surface thereof with a sponge made of PVA (polyvinyl-alcohol) can efficiently remove submicron-sized dust. However, such dust is absorbed into or attached to the PVA sponge, and as a result, when a certain amount of dust has been stored in the sponge, further cleaning effect cannot be expected and it possibly causes a problem of so-called xe2x80x9creverse contaminationxe2x80x9d.
On the other hand, another cleaning method for cleaning the wafer by jet-spraying high pressure water energized by ultrasonic wave or cavitation is effective on cleaning a rather clean wafer having several tens to several hundreds of dust particles attached on the surface thereof. This method is also effective on cleaning extremely contaminated wafer having several hundred thousands of initial dust particles, such as a semiconductor wafer just after CMP (chemical mechanical polishing) processing, which has been put to practical use as a planarization technology of multilayer wiring of the semiconductor device. This are because, different from the method using a brush or the sponge, there is no fear of reverse contamination and thereby, a dust level on the wafer can be certainly lowered. When both of the sponge and the ultrasonic wave are used simultaneously, dust which cannot be removed by either of them individually may be removed by the synergistic effect thereof.
Thus, the wafer can be effectively cleaned by properly selecting or changing the cleaning means depending on a contaminated condition thereof. For example, when an extremely contaminated wafer is cleaned after CMP processing as described above, it needs to be cleaned-at first by the liquid jet spray nozzle, then by the scrub cleaning tool, and finally again by the liquid jet spray nozzle. It is needless to say that other combinations may be employed.
In a case where a plurality of cleaning means are used to clean a single wafer as described above, when the wafer is being cleaned using one cleaning means, other cleaning means shall be retracted into their retracted positions in order to prevent a possible interference between the arms on which respective cleaning means are mounted. Thus, there are problems of longer cleaning period, worse processing efficiency, and rather complicated mechanism and control because of use of the two arms.
In the scrub cleaning tool described above, a self-cleaning operation is necessary to remove dust attached to the brush or the sponge, and accordingly an additional container js required to reserve pure water for the self-cleaning, which requires additional space and brings negative effect on compactness of the apparatus.
In the conventional apparatus, an exclusive mechanism for cleaning a periphery of the wafer is provided to remove dust attached to the periphery of the wafer, which makes both the apparatus and the control complicated.
In view of the above-mentioned situation, the present invention has been made, and an object thereof Is to provide a substrate cleaning apparatus comprising both of a scrub cleaning tool and a liquid jet spray nozzle, which allows either of the cleaning tool and the liquid jet spray nozzle or both of them simultaneously to be selected at need, and provides a shorter cleaning time period, an improved processing efficiency and simplified structure and control.
Another object of the present invention is to provide a substrate cleaning apparatus which requires no additional equipment for self-cleaning.
Yet another object of the present invention is to provide a substrate cleaning apparatus which requires no additional equipment for cleaning a periphery or side surface of a substrate.
Still yet another object of the present invention is to provide a polishing apparatus incorporating the substrate cleaning apparatus described above.
In order to solve the problems described above, the present invention provides a substrate cleaning apparatus for cleaning a rotating substrate, the substrate cleaning apparatus comprising a scrub cleaning tool for cleaning the substrate by bringing the cleaning tool into contact with the substrate, a liquid jet spray nozzle for cleaning the substrate by jet-spraying a cleaning liquid from the nozzle to the substrate, a swing mechanism for simultaneously swinging both of the scrub cleaning tool and the liquid jet spray nozzle on and above the substrate, and a cleaning tool vertical driving mechanism for moving at least the cleaning tool from a position where the cleaning tool is in contact with a surface of the substrate to another position where the cleaning liquid jet-sprayed from the nozzle is applied to the cleaning tool, by vertically moving the cleaning tool independent of the liquid jet spray nozzle.
The present invention further provides another substrate cleaning apparatus for cleaning a rotating substrate, the substrate cleaning apparatus comprising a scrub cleaning tool for cleaning the substrate by bringing the cleaning tool into contact with the substrate, a swing mechanism for swinging the scrub cleaning tool on the substrate, and a cleaning tool vertical driving mechanism for moving at least the cleaning tool from a position where the cleaning tool is in contact with a surface of the substrate to another position where the cleaning tool is in contact with a side surface of the substrate, by vertically moving the cleaning tool.
The present invention further provides yet another substrate cleaning apparatus for cleaning a rotating substrate, the substrate cleaning apparatus comprising scrub cleaning tool for cleaning the substrate by bringing the cleaning tool into contact with the substrate a liquid jet spray nozzle for cleaning the substrate by jet-spraying a cleaning liquid from the nozzle to the substrate, a swing mechanism for simultaneously swinging both of the scrub cleaning tool and the liquid jet spray nozzle on and above the substrate, a cleaning tool vertical driving mechanism for vertically moving the cleaning tool, and a nozzle vertical driving mechanism for vertically moving the nozzle.
The present invention further provides a polishing apparatus comprising a polishing machine for polishing a substrate by bringing a surface of the substrate to be polished into contact with a polishing surface of a polishing tool, and a cleaning machine for cleaning the substrate after the substrate has been polished by the polishing machine, the polishing apparatus characterized in that any one of the substrate cleaning apparatus described above is employed as the cleaning machine.